The affixing of information on the head of a filler gun is known from, for example, U.S. Pat. No. 5,058,637 where a securing means in the form of an elastic stocking is fed onto the filler gun. The stocking is equipped with a display surface for information or advertising, which surface is covered by a transparent cover. The display surface in this known solution is circular and is limited to only a small part of the gun head and the space available for information and/or advertising is limited. The actual method of securing the display surface, which comprises a flexible dead mold cast sleeve, restricts the use of a device of this kind to filler guns which have a special form. This problem can, of course, be solved by manufacturing sleeves of different forms adapted to fit filler guns of different shapes.